The field of the invention is inhalers and pharmaceutical formulations for use in inhalers.
Dry powder inhalers have been successfully used to deliver pharmaceuticals into the lungs, primarily for treatment of asthma and other pulmonary conditions. Use of an inhaler for delivery of a pharmaceutical is advantageous as it is relatively simple, fast, comfortable, and pain-free for the patient. Due to the nature of the absorption within the lungs, inhaled pharmaceuticals tend to be very fast acting. Inhalation usually provides a very fast rise of the level of the pharmaceutical in the blood, when compared to other delivery techniques, such as oral or transdermal delivery. For example, albuterol is a bronchodialator which acts rapidly when inhaled to treat an asthma attack, a condition for which treatment with a solid oral dosage form may be too slow. While this rapid absorption is often advantageous, it can also require relatively frequent dosing via inhalation, to provide a sustained effect. In contrast, oral delivery, which provides absorption of the drug via the gastrointestinal (GI) tract, generally provides a much more slowly acting, but also often a more sustained, therapeutic effect. For many pharmaceuticals, the delay in the onset of the therapeutic effect is a significant disadvantage.
Thus, each pharmaceutical delivery route (via the GI tract, and via inhalation into the lungs) has advantages and disadvantages, depending on the pharmaceutical used and the therapeutic effect desired. However, the advantages of each route have not, until now, been combined, to achieve the advantages of both routes, in a single dose or step.
Many patients must regularly take two or more pharmaceuticals. The pharmaceuticals may act independently to treat unrelated conditions, or they may act together, or complement each other, in treating a single condition. The dosing regimen for combinations of pharmaceuticals often require that they be taken at the same time. This may require taking 2 or more capsules or tablets from different bottles, a combination of such oral dose forms and a pharmaceutical delivered via another route, or some other combination of delivery routes. For example, patients with Type 2 diabetes will often be prescribed doses of insulin, via injection, along with a hypoglycemic drug in an oral dose form.
The need for separate dosing is less convenient for the patient than taking a single dose. The patient must: maintain a supply of both (or all) of the separate pharmaceuticals; remember to take each one; and go through the separate actions of taking each one. Accordingly, the dosing regimen is more complicated, and difficult to maintain (when compared to a single dosing regimen), especially for classes of patients having a disability due to sickness, injury, age, or medical condition.
For patients taking more than one pharmaceutical, complying with their prescribed dosing regimen can be less consistent, due to the need to separately take each of the pharmaceuticals. To achieve the full therapeutic effect of the prescribed pharmaceuticals, it is generally important to maintain consistent compliance. Thus any pharmaceutical delivery techniques which can improve patient compliance will help to improve the patients health. Consequently, for many patients, it would be highly advantageous to be able to combine separate dosing regimens into a single joint dosing regimen. Reducing multiple dosing regimens to a single dosing regimen improves the convenience to the patient, and makes compliance to the prescribed dosing regimen easier, and thus more likely to be consistently followed.
Accordingly, it is an object of the invention to provide a pharmaceutical formulation for use in an inhaler, which provides the rapid onset or effect of an inhaled pharmaceutical, along with the slower onset and/or the longer acting effect of a pharmaceutical delivered via the GI tract.
It is a further object of the invention to provide a pharmaceutical formulation for use in an inhaler which can combine multiple dosing regimens into a single action, to improve the convenience to the patient, and to improve patient compliance to the prescribed dosing regimen.
In a first aspect of the invention, a pharmaceutical formulation includes microfine active particles preferably of about 1-10 microns in diameter and carrier particles preferably of about 10-100 or larger, and preferably greater than 50 microns in diameter. The microfine particles and the carrier particles are both made of an active pharmaceutical compound. The carrier particles and the microfine particles may be the same active pharmaceutical compound, or they may be different active pharmaceutical compounds. At least some of the microfine particles may be attached to and carried by the larger carrier particles.
In a second aspect of the invention, upon inhalation, the microfine particles and carrier particles are separated, preferably through input of mechanical or electrical energy. The microfine particles travel through the throat and pass into the lungs. The carrier particles pass into the throat, and are swallowed. Accordingly, active pharmaceuticals are delivered to both the lungs (for a rapid onset or fast acting effect) and to the GI tract (for a slower onset or a more sustained effect). The swallowed dose is preferably at least 10 times greater in weight than the inhaled dose, and preferably is at least 50, 100, or even 1,000 times greater.